They were both paying tribute to Dolly Parton at the Grammys, and had a chance encounter that didn't end too well.
Source: <a href="https://www.youtube.com/watch?v=KXdOulZ81y8&feature=youtu.be">YouTube</a>
The leaked flyers tease “6+ stages, 35,000+ people, Woodstock legends + more.” The lineup centers around classics, pop, rock, hip hop, latin, country, and EDM.